1. Field of the Invention
The present invention relates to the field of display, and in particular to a manufacturing method for vertical alignment (VA) type liquid crystal display (LCD) panel.
2. The Related Arts
The active thin film transistor liquid crystal display (TFT-LCD) devices are growing rapidly and receive wide application. The TFT-LCD devices available on the market are mostly of the backlight type, comprising a case, a LCD panel and a backlight module disposed inside the case. The traditional structure of the LCD panel comprises a color filter (CF) substrate, a TFT array substrate, a liquid crystal (LC) layer sandwiched between two substrates, and a sealant. The working principle is to apply a driving voltage to the two glass substrates to control the rotation of the liquid crystal molecules of the liquid crystal layer to refract the light from backlight to display.
For the current mainstream TFT-LCD display market, there are three types: a twisted nematic (TN) or super twisted nematic (STN) type, an in-plane switching (IPS) type, and a vertical alignment (VA) type, wherein the VA type LCD shows a higher contrast compared to the other types, and is widely applied to large-size display, such as TV. The known VA technologies are divided into multi-domain vertical alignment (MVA) technology, patterned vertical alignment (PVA) technology, continuous pinwheel alignment (CPA) technology, and polymer stabilization vertical alignment (PSVA) technology. These VA technologies require the design for the CF substrate side or the TFT substrate side to include protrusion or slit, so that the LCD molecules have a pre-tilt angle. Because powered up, the LC molecules are lined up along the protrusion or the slit. When the power is applied, the LCD molecules on the surface of protrusion or slit start moving and carrying the LC molecules in distance to align along the same direction, so as to ensure the entire element to reach stable alignment.
However, these protrusions and slits must be produced in a certain process, such as: in MVA technology, to dispose the protrusions on the CF substrate side or the TFT substrate side, the protrusion requires a special exposure process to produce and the technical requirements on the exposure process is high; while in PSVA technology, a transparent ITO layer must be etched on the TFT substrate side to produce slits. These methods have greatly increased the complexity of the TFT-LCD manufacturing process.